DEFINE LOAD CURVE

This function allows the user to define, read in, or modify MOTION and/or FORCE load curves. As shown in Figure 11.2.4, the user can define the curve type by toggling on either checkbox of MOTION or FORCE. The MOTION curve allows the user to define the tool movement via velocity or displacement control, while the FORCE curve allows user to define a given force applied onto a tool.  If both the MOTION and FORCE curves are defined for a tool, the MOTION curve will overwrite the FORCE curve control. However, the force control can be activated if a death time is set for the MOTION curve (the default death time is the termination time of the MOTION curve).

Figure 11.2.4  Tool Load Curve dialog box

SHOW CURVE

Display the load curve on the eta/DYNAFORM display area. It also provides many options for viewing the graph.

ASSIGN CURVE

This function is used to assign a motion/force load curve to a tool from the list of defined load curves in the SELECT CURVE dialog box. As shown in Figure 11.2.5, the user can select a particular load curve from the list.  Click on the OK to button to confirm the selection and to complete the ASSIGN CURVE operation.

Figure 11.2.5  List Curve

READ

Allow the user to read in an external load curve using the window in Figure 11.2.6.

Figure 11.2.6  Read Curve File

AUTO

This function is used to generate a velocity/displacement/force load curve. If the MOTION option is checked, the MOTION CURVE dialog box illustrated in Figure 11.2.7 is displayed.

Figure 11.2.7  Auto Motion Curve dialog box

 

The MOTION CURVE dialog box enables the user to define either the velocity or the displacement load curve according to the begin time, velocity/displacement and stroke distance. If the VELOCITY checkbox is toggled on, the load curve is plotted as velocity versus time. The DISPLACEMENT option enables the user to plot a displacement versus time load curve. The load curves can be plotted in one of the 3 different types of curve shapes as listed below:

 

TRAPEZOIDAL – Simplified discrete load curve (recommended).

SINUSOIDAL – Smooth discrete load curve.

SINUSOINAL WITH HOLD – Smooth discrete load curve with the maximum velocity held constant for a period of time.

 

After selecting the desired curve shape, the user does the following steps:

 

·         Input the data fields of BEGIN TIME, VELOCITY, and STROKE DISTANCE.

·         Select NO if there is more than one travel phase in the curve, following by selecting curve shape and input the values for a second travel phase in the data fields accordingly.

·         Select YES to create the motion curve.  A dialog box showing the motion curve is displayed. Refer to Section 13.14.8, UTILITIES/LOADCURVE/SHOW LOAD CURVE.

·         If FORCE CURVE is checked, the FORCE CURVE dialog box (as shown inFigure 11.2.8) is displayed.

Figure 11.2.8  Auto Force Curve dialog box

·         Input values in the data fields of BEGIN TIME, FORCE, and END TIME. The default end time is the end time of motion curve.

·         Select OK to create the force curve. A dialog box showing the force curve is displayed. Refer to Section 13.14.8, UTILITIES/LOAD CURVES/SHOW LOAD CURVE.

 

REMOVE

This function is used to remove the applied load curve.  If the REMOVE button is clicked, a warning message (as shown in Figure 11.2.9) is displayed. The user selects either YES/NO to accept/reject the operation.

Figure 11.2.9  Remove Warning

MODIFY

This function is used to edit the current curve. Refer to Section 13.14.4 for more details.

MANUAL

This function is used to manually create a curve by input data points. The dialog box is shown in Figure 11.2.10.

 

The steps listed below are used to manually generate load curve:

·         Select VELOCITY or DISPLACEMENT option.

·         Input TIME and VALUE (velocity or displacement).

·         Select ADD POINT to add next data points.

·         Select OK to complete curve definition and exit the INPUT CURVE dialog box.

Figure 11.2.10  Input Curve dialog box